Revised Abstract R18 DK118460-01: OPTIMIZing carE in Chronic Kidney Disease (OPTIMIZE CKD) Millions of adults have chronic kidney disease (CKD), leading to substantial morbidity, mortality and health care costs. These effects are concentrated in patients with high-risk disease. Several provider- and system-level barriers lead to well-described gaps in care for these patients, contributing to poor outcomes. Population health management (PHM) improves health by aggregating and analyzing data across a population to drive consistent, evidence-based care. CKD PHM using electronic health records (EHRs) can be a sustainable strategy to overcome physician- and system-level barriers. EHR-based PHM could improve the identification of patients with high-risk CKD; increase the use of evidence-based, widely available, and cost-effective interventions; and enhance medication safety. The Kidney- Coordinated HeAlth Management Partnership (Kidney-CHAMP) study (R01DK116957-01A1) is testing the effectiveness of a multi-faceted EHR-based PHM intervention to improve the delivery of evidence-based CKD care in high-risk patients. Specifically, it targets: 1) timely communication of high-risk CKD, 2) implementation of remote nephrology guidance (E-consult) to improve evidence-based CKD care, 3) provision of pharmacist-led medication safety reviews, and 4) standardized CKD patient education. This 42-month pragmatic, cluster randomized controlled trial in ~1,700 high risk CKD patients from 330 Primary care physicians (PCPs) will evaluate the intervention?s effects on key processes of care and kidney disease progression. The proposed ancillary study to Kidney-CHAMP will qualitatively identify barriers/facilitators of the intervention?s effectiveness and response heterogeneity in diverse settings and with diverse patient and provider groups. Participants will be selected using purposive sampling from the PCPs and patients who are randomized to the intervention arm in Kidney-CHAMP study. Semi-structured interviews will be conducted to elicit key physician and patient level predictors that underlie effectiveness of the intervention in diverse settings, which will allow refinements of CKD phenotypes and transportability of the intervention in heterogeneous populations. These deliverables would strengthen future trials and specifically address disparity in CKD care by interviewing patients from vulnerable groups including minorities, low socioeconomic status, and those with multi-morbidity. This ancillary study is highly complementary and valuable to the evaluation of the Kidney-CHAMP intervention. The proposed qualitative work will further refine future efforts to improve the intervention?s implementation, dissemination and use in real practice and diverse healthcare settings.